Aucklanders, you know you’re drinking the Waikato River

Let me begin at the end. This is me yesterday holding a glass of water from the Waikato River after it’s been through the Watercare treatment plant near Tuakau.

I’m standing next to Shayne Cunis, Watercare’s Water Treatment Manager. Shayne has been involved in various battles that Watercare has conducted to try to stop the Waikato River getting even more polluted, and, much to his chagrin, I mentioned him and Watercare’s battles in Parliament a few years back.

This is me drinking the water.

Tastes pretty damn good actually, but by crikey it takes a lot of effort to make it this good.

This is what the river water looks like after it is drawn from the river, screened for big objects and has coagulants added.

Pretty ugly. You may be able to see large globs of muck coagulating on the aluminium sulphate coagulant.

Then this is what it looks like after the coagulated gunk is removed.

Much cleaner but still with a lot of nutrients. There is algae visibly growing on the surface and on the pipes.

Then the river water goes into the really fancy part of the treatment plant which is the membrane filtration – lots of long straws with tiny little holes in them – the holes are 0.035 microns across (micron is one thousandth of the milimetre). So only things that are smaller than 0.035 microns can get through into the straw and to your tap – which stops the protozoa such as giardia and cryptosporidium (from all the animal faeces in the river).

This is what the straws look like when they are out of the water.

After getting through the straws then they go through carbon filters, which apparently have nematodes and other things growing on them which filter the water even further. You can see through the clean water down to the carbon filters in this picture.

Then it gets a bit of chlorine added to kill the viruses and anything else. A bit of fluoride is added, as well as some lime to get the pH right.

And then out comes clean water that is sent in a pipe over the Bombay Hills to contribute about 10% of Auckland’s water – a number that is likely to increase over time as Auckland grows.

This very sophisticated treatment plant cost around $155m. It delivers water at around 19c per cubic metre (1000 litres), which is considerably higher than the cost of the water coming out of the dams in the Hunua Ranges.

The Waikato river treatment plant and pipeline were built after the 1994 drought and were pretty controversial at the time. But it’s here to stay.

What I like about it is that it means that about one in three New Zealanders (Auckland, Hamilton et al) have a very direct interest in the quality of the water coming down the Waikato River because their drinking water is extracted from that catchment. The more polluted that water is, the more expensive and difficult it is to treat it. And if the water gets more polluted, then Watercare will have to invest in even more sophisticated treatment equipment than they have now.

So how bad is the water at the end of the Waikato river?

This is a photo of the mouth of the Waikato taken from the plane yesterday.

Really bad is the answer. It has masses of sediment, lots of nitrogen and phosphorous that feeds algal blooms and heaps of faeces and everything associated with faeces such as bacteria and viruses. There is also a fair bit of heavy metals, some of it natural and some added by Contact’s geothermal plant (they are one of the few geothermal plants that doesn’t re-inject).

A short way upstream of the mouth, the level of faeces near Auckland’s water intake regularly breaches swimming standards. The faeces is largely animal in origin.

In Hamilton they say “Flush twice, Auckland needs the water”. And it’s true that Hamilton’s treated sewerage goes into the Waikato, but only a small fraction of the pollution in the river is due to Hamilton’s sewerage or other point source discharges. Around 70% of all the nitrogen in the river, for example, comes from non-point sources, largely intensive agriculture.

Source: Waikato Regional Council

At the top of the river, as the water leaves Lake Taupō, it is so clean that you can see 12m or more through it. By the time Aucklanders extract it at Tuakau, you can’t see your feet if the water is half way up your ankles.

Median water clarity in Waikato River (Waikato Regional Council)

To get a first-hand view of the river I went for a paddle yesterday, starting at Mercer, past Auckland’s water intake, and pulling out at the Tuakau bridge.

At Mercer I met with Rangi Mahuta and Sally Koia from Waikato Tanui. They are pretty distressed about the state of the river. Tainui are now part of the joint management River Authority which was a Treaty settlement deal. It has some funding to clean up the river and some regulatory tools. The Government has appointed John Luxton to co-chair the Authority with Tuku Morgan, which, given Luxton’s background with Open Country Cheese with its record of pollution, doesn’t fill me with hope. But we shall see.

Joining me on the paddle were Al Fleming and Jon Wenham from Forest and Bird. Al has blogged on the trip too, reflecting

All the rain meant the river was probably even browner than usual – you can see the paddle disappearing into the water.

There were some nice bits of regenerating kahikatea forest, here’s Al in front of some.

We paddled down past the intake for Auckland’s water at this buoy.

And then we came across some pretty average farming practice in these parts.

These animals are unfenced right on the Waikato River. I went over to have a look and they decided I was interesting too, and a big bunch of them came over to have a look at the kayak.

The faeces and urine go straight into the river and the trampling on the edge adds to erosion and sediment. This is what Fed Farmers are defending against regulation.

It is very basic to fence animals out of large rivers, but even this very basic level of good farming practice isn’t in place on the river. We need rules in place to regulate intensive agriculture like this so that we can clean up our rivers.

The real challenge is that getting basic good farming practice in place is only the beginning. Even with good practice there is still a huge run-off of nitrogen from intensive agriculture. As I said in the House back in 2008

Watercare … stated in a submission that discharges from just one industrial dairy development in the Waikato catchment involving Landcorp could mean “the nitrate increase and increased risk of protozoa would cause a decline in water quality”, and “If irrigation was allowed for this one project, summer low flows in the Waikato would reduce by a further 13 percent and river nutrient concentrations could go up by 120 percent.”

Thankfully that particular project didn’t go ahead after the financial crisis but there are plenty more that will take off with dairy prices at high levels. We need clean water rules.

18 Comments Posted

I simply get annoyed when reports display a photo of a west coast estuary and declare that the high faecal contamination is because of farm run-off when there isn’t any. There are two streams feeding the Karkare lagoon. I used one of them as a drinking water supply (from just above the Karekare waterfall)
Also, where there are several sources good science means there should be some attempt to assess their relative contributions. Otherwise resources are misallocated.

An estuary, by definition, is a brackish lagoon on the coast in which freshwater and saline ocean water mix. Thus, estuaries always have a freshwater source – ie, a river – flowing into them. Perhaps it is the case at the Karekare lagoon that there is no farm run-off entering the river. But I can assure you that many other estuaries in our country are suffering nutrient increases largely due to diffuse farm run-off in their feeder rivers.

Russel
No problem with your discussion of sedimentation – it recognises the need to address the particular.
The Waikato is also interesting because it used to be free of hydro dams and had a high flush rate.
After the dams we used to mine much of the sand which kept the flow rate high in many sensitive areas.
Then we decided that was “unnatural” (presumably the dams were natural) and now we have routine floods.

This example is not intended to promote an argument but to keep emphasising that these are complex chaotic systems and we need to be careful about making general claims and assumptions.

Now to the issue of sedimentation. It’s true that there is natural level of erosion and sedimentation, but this is particularly coming out of high country rivers where there is little vegetation to hold the soil in place.

But the current rate of filling in estuaries with sediment is more than 10 times the natural rate, due to forest clearance.

Rivers coming out of catchments with intact forests (and no high country land in the catchment) have very low levels of sedimentation.

The Waikato is particularly interesting in this respect because the high country catchment rivers leading to Lake Taupo have sediment loads higher than the start of the Waikato coming out of Taupo because the lake acts as a giant natural silt trap.

The natural sediment loads at the mouth of the Waikato would be much lower than the current rates, but I can’t put my finger on a number off hand.

Russell,
The NIWA article was about river pollution. And I have little disagreement with it.

However, over enthusiastic local bodies get excited about Faecal Contamination of estuary lagoons which they find have the highest such contamination in their district or region. I lived alongside such a lagoon at Karekare.
When they found these estuarinelagoon faecal contamination levels to be very high they decided it was from sceptic tanks along the Karekare Stream.
When the Herald showed a picture of it (or it might have been the one at Piha) they blamed farm runoff. There isn’t any. So I got involved in the issue back then in the nineties. I asked Council to do the tests and assured them I would do any upgrading necessary. The end result of the research programme was that the tanks were not the problem. Sea birds, dogs and kids do the initial contamination and the warm weather creates a wonderful fermentation pond.
So I was trying to make the point (within a brief post) that these issues are site specific. BIrds do not waste weight on high level treatiment of their own excrement and are a remarkably high source of faecal contamination. The Moa must have done their bit in early days.

But I should have written “the main polluters in these estuarine ponds were birds dogs and children”.

As written it does imply they are the main general polluters of rivers. They are not.

But estuarine lagoon pollution levels have led to much wasted expenditure on “on-site treatment” which makes no difference. Fortunately, we had a pathologist living at the top of the valley – and he made a great contribution to the debate.

‘pastoral farming… is undoubtedly the main source of diffuse pollution… Streams in dairy land are among the most polluted.’

‘There is no doubt that our declining river water quality over the last 20 years is associated with intensification of pastoral farming and the conversion of drystock farmland to dairy farming, particularly in Waikato, Southland and Canterbury.’

WE just have to be realistic and remember that the land above sea level is continually being eroded and the rivers transport the eroded rock and soil to the ocean.
I suspect that an aerial photo of the Nile and Amazon river mouths taken two million years ago would look the same as they do today.

The progression from clear headwaters (as at Taupo) to a murky “delta” is the norm and human contribution in terms of mass is trivial. What is new is the real pollution by toxins and that is what we need to focus on.

We can be reasonably sure that all those herds of elephants and wilderbeast did not “abstain” from ablutions when they frolicked in the great rivers of Africa. And have any of you ever swum among a pod of dolphins when they all decide to let go at the same time?

You may remember the recent report on “pollution hot spots” in our rivers and estuaries. Two of them were lagoons on the Auckland west coast beaches. The pollution was blamed on farm run-off. But there isn’t any.
The main polluters are sea birds, dogs and children. The e-coli levels don’t track population which peaks in December but temperature which peaks in February. These estuarine ponds are giant fermentation tanks.
I am not recommending that we go out and shoot all the birds, dogs and children – but that we focus on good science and spend our money where it counts.

It’s not just pollution and expensive treatment either, but loss of nutrients to the soil.

Human sewage may be a relatively small percentage of the total effect, but its presence in the rivers and lakes and harbours around the country is profoundly offensive to Maori (and many others too). We know how to clean up, time we did.

A tomato grower sued for 1.3 million damages from spray damage to his greenhouse tomato crop.

The source was identifiable and the damaged air was contained within a greenhouse.

The Mesopotamian Code of Hammurabi (1790 BC) also contained early examples of environmental and nuisance law. The Code was strong on compensation for damage.

Law 54 says
“If any one be too lazy to keep his dam in proper condition, and does not so keep it; if then the dam break and all the fields be flooded, then shall he in whose dam the break occurred be sold for money, and the money shall replace the corn which he has caused to be ruined.”

Law 55 reinforces the need to prevent water damage to neighbouring properties:
“If any one open his ditches to water his crop, but is careless, and the water flood the field of his neighbor, then he shall pay his neighbor corn for his loss. ”

The Hammurabi Code noticeably sets out to address the consequences of building failure or failures in farm management, rather than attempting to ensure the safety of the building or the proper management of the farm in advance by consenting processes.

Law 229 says:
“If a builder build a house for some one, and does not construct it properly, and the house which he built fall in and kill its owner, then that builder shall be put to death.”

The old common law doctrines say you should be able to sue a neighbour whose water upstream is cleaner that the water that passes the downstream boundary and hence discharges polluted water to your property.

The problem is the past is that such measurements were expensive and unreliable. Modern biosensors mean this is no longer the case.

The potency of this approach is that one is focusing on a difference in measurements rather than focusing on a standard.

Interesting post. If treated water can be costed at 19 cents per cubic metre, is it feasible then to cost how much is being spent to clean up after every [some useful unit] of pollutants being discharged into the river by agriculture and others?

Not that that should ever be a final measure as I’d hate to imply it was okay to dump in any place without a treatment plant at the end.

Fertilizers, fuel, sewage blamed
Pollution-fed algae, which deprive other living marine life of oxygen, is the cause of most of the world’s dead zones. Scientists mainly blame fertilizer and other farm runoff, sewage and fossil-fuel burning.

If we want to protect our marine environment then we need to give consideration to the amount of shit that’s running into our streams from the farms. Amazingly enough, this will also help other parts of our natural environment.